Redirecting in asp.net?

Question

In my page after sign in am redirecting to home page (This is fixed) but when am trying to click on job apply button,it should check the user is login or not like 

 

if(Id!=0)

Redirect to page.aspx

else

Redirect to login page

In this case after login it should not redirect to home page ,it should be redirect to  page.aspx,for this how to write the logic?